A combine harvester making use of a header with a rotatably driven auger assembly that comprises an auger finger assembly is for example known from EP1749436. FIG. 1 of EP1749436, which is hereby incorporated by reference, shows a simplified side view of a grain header supported on a feeder on the front end of an agricultural combine harvester. In dotted lines there is further shown a rotatable auger assembly of the header. This known rotatable auger assembly comprises an auger finger assembly that comprises multiple auger fingers extending radially outwardly from a rotatably driven tubular auger body at axially and angularly spaced locations. The elongate auger fingers thereby extend from an inwards end through a corresponding opening in the auger body to an opposing outwards end outside the auger body.
As shown in more detail in FIG. 3 of EP1749436 each of the multiple auger fingers is individually mounted by means of a corresponding multiple of finger holders to an excenter shaft. This excenter shaft is mounted inside the auger body and is arranged parallel to and eccentric with respect to the central rotation axis of the auger body, so that the auger fingers make a suitable rotating and telescopic motion during the rotation of the auger body for conveying the crop towards a feeder of the combine harvester. These finger holders are arranged side by side along the axial direction of the excenter shaft, and generally comprise a T shaped structure. Each finger holder comprises a finger bearing with an internal opening in which the excenter shaft can be introduced such that the central axis of the excenter shaft is aligned with the central axis of the internal opening. In this way the finger holder is mounted to the excenter shaft in a way that allows for rotation of the finger holder around the central axis of the excenter shaft. Further the finger holder comprises, attached to this axial finger bearing, a radial finger seat, which an inwards end of the auger finger is mounted. This radial finger seat encloses a generally cylindrical cavity in which the inwards end of the auger finger can be mounted. The central axis of this cylindrical cavity in this way extends radially outward with respect to the excenter shaft, and is generally aligned with central axis of the elongate auger finger, which extends from its inwards end, radially outward with respect to the excenter shaft, through the corresponding opening of the auger body, to its opposing outwards end. Preferably, in order to allow for a secure mounting of the auger finger, that is able to withstand the loads exerted on the finger when performing its crop conveying function, preferably the finger seat encloses the auger finger at the inwards end of the finger over a predetermined length along the length direction of the auger finger, so that a robust and secure mounting is provided.
It is clear that the finger holder must not only allow rotation of the auger finger with respect to the rotation axis, but must also allow for a relative rotational movement of each individual auger finger with respect to the adjacent auger fingers along the axial direction of the excenter shaft. As shown in EP1749436, in order to allow for this relative rotational movement of adjacent auger fingers without the risk of interference of their adjacent finger holders, the width of the axial finger bearing along the direction of the rotation axis is larger than the width of the radial finger seat. It is clear that in this way the maximum number of auger fingers that can be mounted adjacent to each other on a predetermined length of the excenter shaft is limited.
However as the capacity of harvesting machines increases and a more even distribution of the crop flow into the harvesting machine is desired in order to improve the efficiency of downstream processing by the harvesting machine it is desired to provide for an increased number of auger fingers suitable radially and axially distributed along the auger body.
An alternative auger finger assembly is for example known from EP1183939 in which the auger fingers are not individually mounted to the excenter shaft but in a grouped way on three radially distributed finger mounting bars that extend longitudinally parallel to the excenter shaft and are each rotatably mounted to the excenter shaft by means of three axially distributed bearings. The mounting bars however limit the flexibility in the radial distribution of the auger fingers, as it will be difficult to provide for auger fingers at more than the three radial locations of the embodiment shown without causing interference of adjacent mounting bars caused by their relative rotational movement during the rotation of the auger body. Additionally all auger fingers of each of a single mounting bar need to be provided at the same radial location, thereby leading to a less uniform crop flow. Still further the additional elements of the mounting bars increase complexity of the construction thereby complicating assembly and maintenance of the auger finger assembly and further increases the inertia of the auger finger assembly, which leads to higher forces and torques impacting the elements of the auger finger assembly and the need for an increase in the required driving power to be provided by the rotational drive of the auger assembly, especially in the context of higher rotational speeds associated with an increasing capacity of the harvesting machines.
Therefore, there still exists a need for an improved auger finger assembly that overcomes the abovementioned drawbacks and is able to provide for a simple, robust and efficient auger finger assembly that allows for an increase in the capacity and efficiency of the harvesting machine.